modprobe: properly handle errors from init_module
modprobe: properly handle errors from init_module

Effectively catch and the zero and non-zero cases and error out
appropriately. Note that -EEXIST will only ever be returned when
KMOD_PROBE_STOP_ON_ALREADY_LOADED is set as a probe_insert_module flag.

Distrotech/kmod,pmmccorm/kmod,lpereira/kmod,pmmccorm/kmod,Distrotech/kmod,lpereira/kmod,lpereira/kmod,lucasdemarchi/kmod,Distrotech/kmod,pmmccorm/kmod,lucasdemarchi/kmod,lucasdemarchi/kmod